Behold a New Slime Mold
Laura Walker, a doctoral candidate in biological sciences, studies fungus-like organisms known as slime molds. Specifically, she focuses on a group of slime molds known as myxomycetes.
In January 2012, Walker traversed the forests of Costa Rica, searching for myxomycetes as on a research grant from the Organization for Tropical Studies. Myxomycetes are abundant but relatively little is known their ecology, and this is especially true for the soils associated with tropical forests.
On a recent morning, Walker showed me the prized myxomycete she brought back to the lab four years ago. To the naked eye, it looks like a splinter. But under the microscope, a tiny stalk topped by a shiny yellow sphere becomes visible on a sliver of a decayed twig (pictured above).
It’s a new species: Perichaena longipes.
Steve Stephenson, a research professor at the U of A, one of the world’s leading experts on slime molds and Walker’s research adviser, came up with the name.
“When we first saw it, we thought it was a similar-looking species that is really common,” Walker said. “This one looked a little different. But myxomycetes of the same species often appear to be different due to variable environmental conditions, so we thought it was a fluke. But then the next summer, I conducted a larger study in Panama on a fellowship with the Smithsonian Tropical Research Institute and found more.”
She knew she was on to something. Walker went back to her myxomycete specimens from Costa Rica and Panama and re-analyzed them.
“I noticed that since they were so consistent in their appearance, they had to be something else, then with more detailed observation it was obvious,” she said. “We went through the literature and didn’t find anything. I teamed with Dmitry Leontyev – who was working in Dr. Stephenson’s lab as a Senior Fulbright Scholar. Dmitry is an exceptional myxomycete taxonomist and he helped us confirm the new species.”
The U of A researchers described their discovery in the September/October issue of Mycologia, a journal of the Mycological Society of America. The paper, written by Walker, Leontyev and Stephenson, is titled “Perichaena longipes, a new myxomycete from the Neotropics.”
It was Walker’s first published paper as lead author. Adding to her excitement was the journal’s choice to feature a microscopic image of P. longipes on its cover.
Slime molds are not plants or animals, but they share the characteristics of both. They feed on the microorganisms associated with dead plant material, especially bacteria and fungi, and they play an important role in vital ecosystem processes such as nutrient cycling.
The U of A holds the largest collection of slime molds in the United States, with roughly 40,000 specimens kept in Stephenson’s lab.
Stephenson, with funding from the National Science Foundation, is supervising the digitization of 10,000 of the specimens of slime molds housed at the U of A. The three-year project is part of an overall NSF effort to digitize data for millions of biological specimens.
The U of A myxomycetes will be added to the National Resource for Digitization of Biological Collections database, making them accessible to scientists, educators and the public.